In order to increase the quality of automobile gasoline, SINOPEC makes secondary development on the patent technology of absorptive desulfurization of gasoline purchased from ConocoPhillips, to produce low-sulfur clean gasoline having a sulfur content of lower than 10 ppm. SINOPEC has established eight sets of the gasoline-absorptive desulfurization equipment in the first phase, and will build several sets of the equipments in the second phase. The processing of the regenerated flue gas has become an important part indispensable to the equipment construction.
The adsorbent for absorptive desulfurization of gasoline needs to be regenerated by calcining after saturated by absorption, and the regenerated flue gas contains sulfur dioxide in a higher content. In the original patent, sulfur dioxide is removed by absorption with an alkaline solution. However, the processing of waste alkaline solution will result in secondary pollution, and waste the sulfur resources at the same time.
At present, no patent of introducing the flue gas regenerated by absorptive desulfurization of gasoline into the Claus tail gas hydrogenation unit of a sulfur device has been reported yet. This is primarily because that the regenerated flue gas comprises SO2 in a maximum volume content of 5.4% and O2 in a maximum volume content of 3.0%, and has a temperature of only 160° C., while the Claus tail gas hydrogenation catalyst in the prior art requires the SO2 volume content of less than 0.5%, the O2 volume content of less than 0.05% and a temperature of more than 280° C. Thus the Claus tail gas hydrogenation catalyst in the prior art cannot satisfy the requirements on hydrogenation of the flue gas regenerated by absorptive desulfurization of gasoline.